Vacuum conveying system



Oct 1969 D. NYSTRAND 3,473,800

VACUUM commune s'zsm/x Filed July 11, 1967 3 Sheets-Sheet 1 Oct. 21,1969 E. n. NYSTRAND 3,473,300

VACUUM commune SYSTEM Filed July 11, 1967 3 Sheets-Sheet 2 744. Fr all!2-71.! llvfllylna l-ilrllirffsrllnrldi ,lllrlllnilall 7457! nmx W: mm27/7 4 7 M74 47/ N J Q g K \m x m m ma mm nited States Patent 11.5. Cl.27174 14 Claims ABSTRACT (IF THE DISCLOSURE In a system for transportinglimp flexible articles, a device is provided for controlling applicationof suction pressure to hold an article on a moveable conveyor, andapplication of an above atmospheric pressure to accurately expel anddeposit the article on a receiver. The control device includes a valvebody having an interior cylindrical bore in which a vane is mounted forturning movement about the longitudinal axis of the bore. The

bore is connected to a vacuum pump which applies a suction force throughan opening in the valve body to hold the sheets on a mesh-belt carrier.The suction force is effective until the vane turns to cover the openingand thereby effectively seals the opening to the suction force.Substantially simultaneously, a positive pressure air passageway in thevane is aligned with the opening and the positive air pressure ejectsthe article to the receiver. The vane extends to and in sealingengagement with the bore wall of the valve body so that the positivepressure is ineffective until the vane is aligned with the opening.

This invention relates to apparatus for transporting limp, flexiblearticles such as, for example, creped tissue sheets, and diapers fromone location to another by employing a suction pressure to maintain thearticle in contact with a continuously moving carrier and employing anabove atmospheric air pressure to remove the article from the carrier.The invention relates more particularly to an improved valve forcontrolling the suction and above atmospheric air pressures acting onthe article and to a system incorporating the valve.

An apparatus of the aforementioned type, which is referred to herein byway of example and not by way of limitation, is shown and described inUS. Patent application Ser. No. 505,259, now Patent No. 3,399,587,assigned to the assignee of the present invention. In such apparatus,which is particularly adapted to receive articles, such as, for example,limp sheets of creped tissue and deposit them onto a tissue web, acontinuously moving endless air pervious conveyor is provided having anupper run and a lower run. A chamber is provided above the lower run ofthe conveyor and is alternately maintained below atmospheric pressure tocreate a suction force at the lower surface of the lower run capable ofmaintaining the tissue sheet in contact therewith, and above atmosphericpressure which positively urges the sheet from the conveyor when itreaches a predetermined location relative to the web.

In such apparatus, the below atmospheric and above atmospheric pressureswithin the chamber are controlled by a suitable valve arrangement. Thepresent invention is principally directed to a valve arrangement usefulin the aforementioned and similar apparatus and systems.

It is the principal object of the present invention to provide anefiicient and effective apparatus and system of the type described.

Other objects and advantages of the invention will become apparent withreference to the following description and the accompanying drawings inwhich:

FIGURE 1 is a fragmentary, perspective view of an apparatus showingvarious of the features of the present invention;

FIGURE 2 is a fragmentary, enlarged, partially sectional and partiallybroken-away elevational view of a portion of the apparatus taken alongline 22 of FIGURE 1;

FIGURE 3 is a fragmentary, sectional view taken along the line 33 ofFIGURE 2;

FIGURE 4 is a fragmentary, sectional view similar to that of FIGURE 3,but showing certain of the elements in a different operational position;

FIGURE 5 isan enlarged fragmentary plan View of a portion of theapparatus seen in FIGURES 2-4;

FIGURE 6 is a plan view of the apparatus of FIGURE 1 on a reduced scale;

FIGURE 7 is a fragmentary, enlarged sectional view of an alternateembodiment of the invention; and

FIGURE 8 is a diagrammatic view of a phase adjustment for the valve.

As shown in the drawings for purposes of illustration, the presentinvention is embodied in a sheet transfer apparatus (FIGURE 1) which,very generally, includes a first article carrier 9 adapted to receive anarticle such as, for example, a sheet 10 and convey it to a transferstation 11 where it is transferred to a receiver, which may bestationary, but herein there is a web 12 supported on a second carrier13. In this embodiment, each of the first and second carriers is in theform of a continuously moving endless belt. These belts, which aredesignated by the numerals 15 and 17, respectively, are formed of an airpervious material such as close meshed screen, and the sheets aremaintained in contact with the carrier 9 and the web 12 of the carrier13 by suction and are ejected from the carrier 9 onto the web 12 by anatmospheric pressure in a manner hereinafter described. In thisinstance, both the sheet 10 and the web 12 are formed of a light,flexible material such as creped tissue but the apparatus could ofcourse be utilized with other materials, for example, an assembleddiaper.

In accordance with the present invention, the sheets are accurately andpositively transferred at the transfer station 11 through the action ofa control device 21 which includes a hollow valve body or housing 23within which rotates a vane 25 (FIGURES 2-4). The control deviceprovides a suction pressure adjacent a surface of the first carrier belt15 until the sheet is in approximate alignment with a predeterminedposition on the web 12, at which time the suction pressure is releasedand an above atmosperic pressure is substituted to release the sheet 10and expel it onto the web. The sheet is attracted to and retained by theweb 12 by virtue of a suction or vacuum box 27 which is positionedbeneath the belt of the carrier 13.

Referring now to the apparatus in greater detail, the sheets aredelivered to an entry side of the carrier 11 by an endless inputconveyor 29 (FIGURE 1) which receives the sheets from a supply sourcesuch as, for example, a web severing and spacing mechanism, which is notshown herein, but is shown in Patent No. 3,399,587, referred to above.The sheets are carried on the upper, generally horizontal run 31 of theconveyor 29. The discharge end of the upper run 31 is disposedimmediately beneath the entry side of the lower run 33 of the sheetcarrier belt 15, which is longitudinally aligned (i.e., from left toright in FIGURE 1) with the input conveyor 29.

To facilitate transfer from the input conveyor 29 to the sheet carrier11, and to maintain the spacing of the strips 10 along their path oftravel, the conveyor 29 and belt 15 of the carrier 11 travel at the samesurface speed, with the lower run 33 of the upper belt positioned inclosely spaced relation to the upper run 31 of the lower belt. Thus, asheet entering the nip between the belts travels forwardly with bothbelts until leaving the upper run 31 of the conveyor 29 at itshorizontal supporting roller 35.

To support the belt of the sheet carrier 9, a pair of horizontallyspaced entry and exit rollers 37 and 39 are journaled for rotation onsupporting shafts 40 and 41 (FIGURES 1 and 6) extending transverselybetween front frame posts 43 and a rear support frame 47 which extendslongitudinally between the spaced rollers and adjacent the far side(FIGURES l and 6) of the belt 15. The rollers are disposed between upperand lower runs of the belt 15 with the exit roller shaft 41 connected toa drive through a gear box 49 (FIGURE 6) which, in turn, is driven by ahorizontally disposed drive shaft 51 extending to a gear box 53. Aninput gear 55 for the last mentioned gear box is connected to and drivenin timed relationship to a cutter (not shown) for the sheets 10 and theinput carrier 29 for the sheets 10.

Adjacent the entry roller 37 is disposed a vacuum or suction box 57(FIGURE 1) which is effective to cause a suction force at the lowersurface of the lower run 33 of the sheet carrier belt 15 adjacent theentry end thereof. The suction box is supported in a suitable manner bythe frame 47 and has a width approximately that of the belt. The forwardend wall 59 of the suction box is arcuately curved and spaced adjacentto the entry side roller 37 to provide a suction force over thedischarge end of the input conveyor 29 to assure continued uninterruptedmovement of the sheet 10 from the latter to the sheet carrier. Herein,the suction box is formed with a pair of opposite side walls 61, a topwall 63 sloping downward from the arcuate end wall 59 to a smalleropposite end wall 65, and a horizontal bottom plate 67. The latter isperforated with suitable intake openings and is disposed parallel to,and at the upper surface of, the lower run of the belt to afford suctionacross the width and length of the box. The interior of the suction boxis connected by a duct (not shown) to a suction source such as a vacuumpump to exhaust air from the box. Thus, a suction force is provided forthe length of the suction box 57 to hold the sheets 10 to the lower runof the belt as the sheets travel forwardly (i.e left to right in FIG. 1)to the entry side of the transfer station 11 at which is located thecontrol apparatus or valve 21.

The leading end of a sheet 10 entering the transfer station 11 continuesto adhere to the underside of the belt 33 due to a suction force on thebelt generated through a chamber 69 which is connected to a suitablevacuum source through a hollow bore 71 (FIGURES 3 and 4) in the valvebody 23 and through a conduit 73 leading to the vacuum source, which maybe a vacuum pump or the intake of a blower (not shown). The chamber andvalve body are suitably supported in the space between the upper andlower runs of the sheet carrier belt 15 by horizontally spaced brackets75 (FIGURE 6) fixed at their rear ends to the frame 47. As best seen inFIGURES 2, 3 and 4, the forward ends of the brackets 75 are fastened tothe upper side of the valve housing at the opposite ends of the latter.The brackets are in the form of a horizontal palte 77 stifiened by anupstanding tapered plate 79 (FIGURES 3 and 4) extending rearwardly tothe frame 47.

The ends of the valve housing 23 attached to the brackets 75 aregenerally square in cross section (FIG- URE 1) and intermediate them isa longitudinally extending center portion having an uppersemicylindrical outer wall 81 integrally joined to opposite longitudinalside walls 83 and 85 (FIGURES 3 and 4) which extend downwardly to ahorizontal bottom wall 87 abutted against the top surface of an upperwall 89 of the chamber 69, the latter being secured to the bottom wallof the valve body by screws 90.

The cylindrical bore 71 in the valve body extends longitudinally alongthe full length of the valve body 23 and is concentric with the roundedouter top wall 81 of the housing. To close the bore 71 at the ends ofthe housing, end caps 93 (FIGURE 2) are fastened at the opposite ends orthe housing with a radially outer annular flange 95 on the end capsabutted against a vertical end wall 97 of the housing body and with anaxially inwardly projecting annular boss 99 projecting into the bore andabutting against a cylindrical wall 101 defining the bore 71.

To facilitate connection of the exhaust conduits 73 to the cylindricalbore 71, tapped bosses 103 are provided in the rear vertical housingwall 85 adjacent the opposite ends of the cylinder body and the exhaustconduits 73 are threaded into the tapped bosses. The air being drawnfrom the valve body bore 71 enters the later from the chamber through aplurality of openings 105 in the bottom wall 87 of the housing, theopenings 105 being aligned with similar openings 107 in the top wall 89of the chamber 69. In the present instance, the aligned openings 105 and107 are aligned vertically and lie along a longitudinal line extendinggenerally the full length of the valve body. As best seen in FIGURES 24,the openings are radially aligned with the longitudinal axis of the bore71. When air is being exhausted from the chamber 69 and the lower run 33of the belt 15, it travels along the path shown by the directionalarrows in FIGURE 4, namely, upwardly through an apertured bottom plate109 and into a hollow interior 110 of the chamber 69, through theopenings 107 in the top wall of the chamber and aligned openings 105 inthe bottom housing wall 87, along the cylindrical bore 71, to theexhaust openings in the bosses 103 and through the conduits 73 to theexhaust pump (not shown).

In accordance. with the present invention, during the time in which thesheet is in the transfer station 11, i.e., beneath the perforated plate109, the valve vane 25 moves into a position to change essentiallyinstantaneously the inward suction pressure in the chamber 69 to anoutward positive pressure of air to expel the sheet 10 to the webcarrier 13 which, in the present instance, has its upper run and the web12 about one-half inch beneath the sheet 10 being transferred. Toachieve this quick and accurately timed change of pressure, the outerend 113 of the vane seals the openings 105 from the suction of thecylindrical bore 71 and, substantially simultaneously, air is deliveredunder pressure through hollow passageways 115 in the vane to theopenings 105 which are now aligned with the passageways 115 in the vane.Herein, the volume of the chamber 69 is made relatively small by havinga narrow spacing between the perforated plate 109 and the top wall 89 sothat the interior 110 of the chamber quickly changes from a suctionpressure to a positive or above atmospheric pressure.

Because the edge of the vane 25 which engages the wall of the bore 71 isnarrow relative to the cross-sectional area of the openings 105 in thewall of the bore, the vane delivers air under pressure for only a smallportion of its cycle of rotation. The positive pressure in the hollowpassageway 115 in the vane is sealed during the major portion of itsrotational cycle by the cylindrical wall 101 of the bore against whichit is in contact. In this respect, the edge of the vane includes anelongated bar 119 of rectangular cross-section fastened in alongitudinal groove 121 at the radially outwardly projecting end of thevane. The seal bar 119 extends radially outwardly from the vane andslides on the cylindrical Wall and is preferably made of a material suchas, for example, nylon, which will slide along the cylindrical wallwithout undue friction or wear. The seal bar extends longitudinallyacross the full length of the vane and is provided with a series ofradial openings 122 aligned with and constituting a portion of theradial passageways 115.

In the present instance, the vane 25 is in the form of an elongatedblock of generally rectangular cross section, except for tapering sidewalls 124 at the end carrying the seal bar. A longitudinal bore 123 ofcircular cross section extends the full length of the vane betweenopposite end walls 125 (FIGURE 2) and is disposed medially betweenopposite longitudinal side walls 126 of the vane and intersects theradial passageways 115 so that the latter are in fluid communicationwith the longitudinal bore 123. The vane extends longitudinally in thevalve body bore 71 between the opposite end caps 93 and is mounted forrotation about the longitudinal axis of the bore 123 by stub shafts 129fixed to the opposite ends of the vane and journaled in bearings 131seated in the respective end caps 93 for the valve housing. Circularbosses 133 on the stub shafts are telescoped into the opposite ends ofthe longitudinal bore 123 and outwardly projecting flanges 135 areabutted against and secured to the end walls 125 of the vane by screws137. On each stub shaft adjacent the flange 135 is a reduced diameterportion 139 which is sized to fit into the bore of the inner bearingrace which abuts an inner and radially directed shoulder on the shaft.To limit longitudinal movement of the shaft, a retaining collar 141 isfastened to the stub shaft adjacent the outer radial wall of the bearing131, the latter being held against longitudinal movement in its end capopening by a pair of Tru-Arc rings 143 abutted against opposite sides ofa bearing and seated in grooves in the wall of the end cap opening 145.

To deliver air under pressure to the interior passageway in the rotatingvane, each of the stub shafts is provided with a longitudinal bore 147extending the full lengt of the respective shafts. The inner end of eachshaft bore opens into the longitudinal bore 123 in the vane and theouter end of each shaft bore is in fluid communication with an attachedair conduit 149 (FIGURE 6). The latter is connected to a stub shaft by asuitable union 151 which permits the stub shaft to rotate Withouttwisting the conduits which lead to the pressure pump (not shown). Thus,air under pressure enters the opposite conduits 149 and moves throughthe stub shaft bores 147 to the longitudinal passageway or bore 123 inthe vane and then moves radially and outwardly through the passageways115 to the seal bar 119. When these radial passageways in the vane arealigned with the openings 105 in the bottom wall 87 of the valve housing(FIGURE 3) the air under greater than atmospheric pressure leaves thelatter and enters into the interior of the chamber 69 to exit downwardlythrough the perforated plate 109 and through air pervious belt to expelthe strip to the lower web carrier 13.

To time the rotation of the vane to the position of the strip 10 so thatthe strip 10 ejects at the proper time to the web carrier 13, the vane25 is rotated by a driving connection 153 (FIGURE 6) with the drivesheet conveyor 11. The driving connection is in the form of a driveroller 155 fixed to one of the stub shafts 129 and a timing belt 157disposed between this roller and a belt roller 159 keyed to the driveshaft 51 for the gear box 49 driving the carrier roller 39.

The placement of the sheets in relatively precise positions on the web12 with a right angle change in directions is difficult to achieve as itinvolves a consideration of the inertia, i.e., the continued forwardmotion of the sheets as the air blast is pushing the sheets down to theweb 12 and also the alignment of the vane with the opening 197 at theproper instant When a sheet is disposed beneath the chamber. Inaccordance with another aspect of the invention, the placement can becontrolled and adjusted for misalignments while the systems is inoperation. To this end, the belt 153 driving the roller 155 and attachedvane shaft 129 is controlled by adjustment means 160 (FIGURE 8) whichincludes a threaded adjustment screw 161 and traveling rollers 162 forshifting the belt 157 relative to the rollers 155 and 159. Morespecifically, the belt 153 may be disposed about a second set of spacedrollers 163 and 164 fixed to a support plate 165. The belt is formedwith an upper loop intermediate the rollers 155 and 159 to receive theupper one of the traveling rollers 162 and is formed with a lower loopintermediate the lower rollers 163 and 164 to receive the lower one ofthe traveling rollers 162. These traveling rollers are secured to andjournaled in a carriage 166 guided for reciprocation in said supportplate for movement along a vertical path. The upper end of theadjustment screw is attached to the carriage to move the latter withturning of the screw in a nut 167 fixed to the support plate 165. Byincreasing or decreasing the size of the upper loop between the rollersand 159 with turning of the adjustment screw 161, the angular positionof the vane and its roller 155 can be adjusted relative to the angularposition of the roller 159 with a relatively fine adjustment. Thus, theposition of the deposited sheets can be adjusted to compensate forchanging conditions and to provide an initial alignment with ease.

It will be recalled that the roller 159 is being driven by the gear box53 and shaft 51 in direct phase with the roller 137 driving the endlessbelt 15 so that the shifting of phase between the rollers 155 and 157results in a change in phase between the sheet on the carrier 15 and therotatable vane.

In accordance with one embodiment of the invention, a more uniform andaccurate transfer of the sheet is obtained by programming thearrangement of holes 169 (FIGURE 5) in the perforated bottom plate 109of the chamber 69. That is, the holes are programmed to distribute theair in such a manner that the sheet travels more evenly from the chamberto its predetermined location on the web 19. Herein, the holes areprogrammed by size with the smallest diameter holes aligned in twocentral longitudinal rows 171 (FIGURE 5) approximately at the middle ofthe plate and with parallel rows of holes of progressively largediameters in each of the adjacent outer rows 173. The largest diameterholes are aligned in longitudinal rows paralleling and adjacent to anopposite longitudinal edge of the plate. For example, the hole sizes maybe inch in diameter for the holes in rows 171, and have an increase of 4inch in diameter in each of the next outward rows 173 until the outerrows 175 in which the hole diameters are of an inch.

A non-programmed perforated plate having holes each with an identicaldiameter has been successfully employed on the chamber 69 and may beused in lieu of the programmed plate simply by removing a series ofbolts 177 threaded into opposite pairs of depending side walls 179 ofthe chamber 69. The perforated plate 109 abuts the lower edges of theside walls 179 and the lower edges of a pair of transversely spacedspacer plates 181 (FIGURE 2) which extend vertically from the plate 109to the top wall of the chamber housing. The interior 110 of the chamberis provided with a contoured wall 183 which slopes from the centerdownwardly and outwardly through a series of steps or lands to each ofthe longitudinal side walls 179. The hollow space in the outer sideportions of the chamber is thus decreased from the hollow space at thecenter of the chamber beneath the chamber openings 107 to providechanges in volume which will result in a relatively uniform velocity ofair flow through the plate and belt 15.

In accordance with another aspect of the invention the seal bar 119 maybe provided with a trailing sealing portion 187 (FIGURE 8) on thecounterclockwise side of the clockwise rotating vane 25. This trailingsealing portion briefly seals the openings 105 as the vane rotates awayfrom the position of FIGURE 3 so that the sheet being expelled isaflorded a longer period of time to travel to the web 19 prior to thereturn of the vacuum pressure which tends to return to the sheet to thechamber 69. The trailing portion of the vane therefore seals theopenings 105 against the return of a suction which would pull the sheetback toward the perforated plate 109, if the same has not yet adhered tothe web 19 and to carrier 13.

From the foregoing, it will be seen that the present invention isdirected to a simple and eflicient apparatus and thin sheet of crepedtissue, from a moving carrier to a moving receiver. In its preferredform, a hollow pressurized vane moves into position over an outlet portin a cylinder bore to cut off a chamber from the vacuum pressure in thebore and to connect the chamber with the air above atmospheric pressurein the vane. The'air above atmospheric pressure expels the sheet fromthe perforated plate to the receiver and, as the vane continues torotate, the chamber is again connected with the vacuum pressure in thebore for the larger portion of the cycle of rotation of the vane.

I claim:

1. In an apparatus for conveying an article by means of a continuouslymoving air pervious carrier, a control device comprising means defininga hollow chamber adjacent at least a portion of the path of the carrierin fluid communication with the carrier along said portion of said p avalve body having an interior cylindrical wall defining a bore anddefining an opening permitting fluid communication between said chamberand said bore,

means for establishing a vacuum within said bore effective to create asuction force at the surface of the carrier,

a vane mounted within said bore for turning movement about an axisextending longitudinally of said bore,

said vane extending radially from said axis into sealing engagement withsaid cylindrical interior wall,

means defining an air passageway for conveying air under pressurethrough said vane to the wall-engaging surface thereof, and means foreffecting turning movement of said vane about its axis between positionsin which the said passageway within said vane is out of communicativealignment with said opening between said bore and chamber, wherein saidchamber communicates with said bore and a suction pressure is maintainedat the surface of the carrier effective to maintain, an article inengagement with the carrier, and a position in which said passageway isin communicative alignment with said opening, wherein said chamber isplaced under a positive air pressure effective to cause an article inengagement with the carrier to be I ejected therefrom. I

2. A device in accordance withv the combination of claim 1, in whichmeans are provided to move said vane in timed relation to movement ofthe article. 4

'3. A device in accordance with claim Zin which said means to move saidvane rotates said vane at'a constant speed.

' 4. A device in accordance with claim 1, which said passageway in saidvane extends longitudinally of said vane along the axis of movementthereof as well as radially from. the axis to the Wall engaging surface,of said vane. i

5. A device in accordance with claim 1 in which a seal is provided onthe outer end of said vane at its trailing side so that at leastatmospheric pressure is main: tained in the chamber long enough totransfer the article from the carrier.

' 6. Adevice in accordance with claim l whichsaid hollow chamber has avolume related to the flow rate of air h qush sai b r ite. t fl w. rate1 r th oug said vane so that the pressure within the chamber can bechanged quickly to and between a value significantly below atmosphericand a value significantly above atmospheric. I h

7. A device in accordance with claim, 1 in which means are providedintermediate said chamber and the carrier to effect generally uniformdistribution of the air to produce an even transfer of the article. 1

8. A device in accordance with claim 3 in which means are-provided toadjust the angular position of the vane relative to the position of thearticle on the carrier while the carrier is runing and the v ane isrotating.

9. The deviceof. claim 1 in ;which said.chamber extends across the widthof the carrier a distance at least equal to the width of the article. vv

10'. The device of claim 1 in which the wall engaging portions of saidvane extend circumferentiallyto cover the width of the opening betweenthe bore and chamber, the-width of said opening being a small portion ofthe circumference of said bore so that said chamber is connected to saidvacuum for the major portion of the cycle or rotation of the vane.

'11. In a system for transferring an article-such as a thinflexiblesheet, means including a continuously moving air perviouscarrier having a suction-*force'at its surface for moving a sheet alonga path of'movement in a predetermined direction, a receiver disposedbeneath said moving carrier to receive a sheet from said-moving carrierat a position along said path, means for establishing a positive forceof air to eject said sheetdownwardly from said moving carrier to saidreceiver, and means including a valve'having a rotatable vanefor-controlling the application of the suction force to a portion ofsaid carrier for a major portion of a cycleof rotation of said valve tomaintain suction pressure at the surface of said air pervious carrierand the application of the positive force to eject said sheet downwardlyto said receiver.

v12. A system in accordance with claim 11in which means are connectedbetween said movable carrier and said Vane to rotate the latter'in'timed relationship-to the speed of carrier travel-to enable accuratetiming'of the ejection of the sheet. 13. A'system inaccordance withclaim 12 in which means are provided to adjust the angular position ofthe vane'relative to the position of the sheet'on the carrier while the-vane is rotating and the'carrier'is moving so that the "sheet rn'ay beaccurately positioned on the receiver. I a

14'. A system in accordance with claim 12' in which saidmeans,'including the valve, also includes an air'charnber disposed abovesaid '"sheet' carrying surface of said moving carrier and in fluidcommunication with said valve. and in which said'receiver is acontinuously moving, air pervious carrier'having asheet receivingsurface spaced vertically from said first-mentioned carrier'and movingat-a right angleto said predetermineddi'rection.

References Cited UNITED STATES LPATENHTSY 3,081,996 3/1963 Hajos 271 :r4

EDWARD-A. sRo A, Primary exa ner;

Dedication 3,4-73,800.Emst Daniel Nystmnd, Green Bay, K is. VACUUM CONVEY- ING SYSTEM. Patent dated Qct. 21, 1969. Dedication filed Dec. 17,

Company.

